This invention relates to a method for weaving a pile fabric on a gripper Axminster weaving machine, whereby weft yarns are brought between binding warp yarns and tension warp yarns so that a backing fabric is woven, while pile threads are so introduced that they are interlaced by weft yarns according to a three-shot weave, so that each pile yarn is passed around a weft thread as a pile tuft with upright pile tuft legs, and while in the course of successive weft insertion cycles alternately one weft yarn alone and two weft yarns one above the other are inserted between the warp yarns.
This invention also relates to an Axminster pile fabric, in particular an Axminster carpet, comprising a backing fabric woven out of weft yarns and warp yarns, in which according to successive weft lines alternately one weft yarn alone, respectively two weft yarns running one above the other are inwoven, and in which pile threads are interlaced by weft yarns according to a three-shot weave, so that each pile yarn is passed around a weft thread as a pile tuft with upright pile tuft legs.
Gripper Axminster weaving machines comprise a shedforming device and a weft insertion mechanism in order in the course of successive weft insertion cycles in each case to bring a weft yarn into a shed formed between warp yarns, so that a backing fabric is formed. This weft insertion mechanism can be provided with two weft insertion means in order in each operating cycle to be able to insert a respective weft yarn at two different insertion levels.
The weft yarns can be inserted by means of rapiers, by means of a projectile or by a so-called needle insertion. With the latter method a weft yarn is pushed double in loop shape through the shed by means of a long needle with an eye from one fabric side over the entire weaving width. On the other fabric side the weft loop is received by a bobbin which pulls an edging thread through the loop. Subsequently the needle returns to the former fabric side, while one tuft of the inserted loop slides into the eye of the needle. With each needle insertion a weft yarn is therefore provided in the shed running back and forth over the width of the fabric. This weft yarn is represented as two threads in fabric cross-sections.
Since such a back and forth running weft yarn has the same function as a weft yarn which only extends from one fabric side to the other, and is also inserted by one and the same weft insertion means in one and the same weft insertion cycle, this must in the context of this patent application be considered as one weft yarn.
The term "weft yarn" in this patent application, and in particular in the claims attached hereto, therefore refers both to a weft yarn only extending from one fabric side to the other and to such a back and forth running weft yarn.
Furthermore gripper Axminster weaving machines are also provided with a series of upwardly and downwardly rotatable pile rapiers, and for each pile rapier a pile loader in which a number of different pile warp yarns are provided. Each pile rapier can in an upwardly rotated position grip the extremity of one of the pile warp yarns in its pile loader. In the course of its downward rotation the rapier pulls the pile warp yarn out of the pile loader. Subsequently this is automatically cut through by a cutting device so that a well-defined length of the pile warp yarn is taken along by the rapier. This piece of pile warp yarn (called "pile thread" in that which follows) is in the course of the further downward rotation of the rapier brought to the edge of the fabric, and is so brought there in relation to the weft insertion path of a weft insertion means that it is interlaced in the backing fabric by the weft yarn inserted thereafter by that weft insertion means. The pile threads are inwoven in the backing fabric as U-shaped pile tufts, with upright pile tuft legs passed around a weft yarn.
Each pile loader can be brought by means of a jacquard device into a number of different positions, so that in each position the extremity of another pile warp yarn comes into reach of the pile rapier working together therewith. In that manner pile can be formed with a great number of different colors (up to 12), while no dead pile warp yarns have to be inwoven. This results in a particularly low pile yarn consumption.
A weaving method exists, known by the name of "3-shot Corinthian", whereby on a gripper Axminster weaving machine in each weft insertion cycle one weft yarn is inserted between warp yarns, and whereby pile is formed according to a three-shot weave. According to this weaving method a backing fabric is formed in which next to each other alternately one weft yarn and two weft yarns one above the other are inwoven by binding warp yarns. In this backing fabric tension warp yarns extend between the weft yarns inwoven one above the other and along the back of the weft yarns inwoven alone. The pile threads are in each case interlaced by the top weft yarn of the two weft yarns inwoven one above the other. This weaving method produces pile tufts with a good anchorage in the backing fabric and with good upright standing pile tuft legs. Furthermore the pile yarn consumption is minimal since the pile threads are not woven through to the back of the backing fabric.
This weaving method however has the great disadvantage that there are three weft insertion cycles in order to form one pile tuft row. The productivity of this weaving method is consequently not very high.
This "3-shot Corinthian" weave have never been woven with double weft insertion because of the following list of reasons.
From GB512962 an Axminster weaving machine is known which is provided for alternately inserting one and two weft yarns, with which this weaving method could be applied with a high productivity. A number of other problems and disadvantages are however not solved with this.
The required weaving machine has two weft insertion means with which in the course of the same weft insertion cycle two weft yarns have to be inserted. The pile rapiers have to hold the pile threads between these two weft insertion paths during the double weft insertion without moreover impeding the movements of the weft insertion means. This is not possible with pile rapiers with the usual shape and dimensions.
Another problem lies in the fact that, even were pile rapiers provided with limited dimensions of the pile rapier jaws, the weft insertion paths would still have to be placed rather far from each other in order that the pile rapier jaws would not impede the movement of the weft insertion means. This would mean that a rather large shed has to be formed between the warp yarns. Because of this no high weaving speed would be able to be achieved.
A problem could also further occur during the beating-up of the two weft yarns located one above the other. During the beating-up these weft yarns could be pulled against the pile rapier jaws by the binding warp yarns. In the course of the beating-up the pile threads held by the pile rapier jaws could become caught between these two weft yarns, with the result that they are torn out of the pile rapier jaws.
In order to be able to weave fabrics with a rather short pile the points of the pile rapier jaws must furthermore be as close as possible to the holding fingers on the fabric edge. In the course of the beating-up of the two weft yarns inserted one above the other the bottom weft yarn could push the pile rapier jaws upward, which could result in the formation of pile tufts with pile tuft legs of unequal length--so-called J-tufts.
Weaving methods are known whereby pile tufts are formed according to a two-shot weave and whereby one weft yarn is inserted per cycle. According to these methods one pile tuft row is therefore formed per two weft insertion cycles, but with the thus obtained fabrics the good pile anchorage is not achieved which is obtained with fabrics with pile formation according to a three-shot weave.
The purpose of this invention is to provide a weaving method with the properties mentioned in the first paragraph of this specification, which can be implemented without any problem on the existing gripper Axminster weaving machines at high weaving speeds, and which produce fabrics with a proper pile formation according to a three-shot weave, but whereby one pile tuft row can be formed per two weft insertion cycles.
This purpose is according to this invention achieved because of the fact that with the weaving method described in the first paragraph of this specification, each pile thread is inwoven by a weft yarn inserted alone, which extends along the pile side of the tension warp yarns.
In the course of the weft insertion cycles in which two weft yarns are inserted one above the other the pile rapiers must not apply any pile threads to the fabric edge. The pile rapiers can therefore remain above the weft insertion paths. This means that these weft insertion paths can lie close to each other, so that the shed formed between the warp yarns can be kept relative small. Because of this high weaving speeds can be achieved.
In the course of the weft insertion cycles in which one weft yarn is inserted alone the pile rapiers must provide pile threads in an inweaving position near to the fabric edge. Since only one weft yarn is inserted the pile rapiers must moreover only leave one weft insertion path free. Because of this the pile rapier jaws can be implemented with a normal shape and dimensions. Since below the weft yarn which interlaces the pile threads no second weft yarn has to be beaten up, there is also no danger that the pile threads held by the pile rapiers are torn out of the pile rapiers in the course of the beating-up of this weft yarn, or that the pile rapier jaws are pushed upward in the course of the beating-up.
The beating-up of the weft yarn which interlaces the pile threads therefore occurs in exactly the same circumstances, and therefore equally without any problem, as with a weaving method whereby one weft yarn is inserted per weft insertion cycle on a gripper Axminster weaving machine.
Furthermore according to this method a fabric is obtained with good upright standing pile tuft legs and with a good anchorage of the pile tufts in the backing fabric.
Because of the fact that the weft yarns inserted alone are inwoven in the backing fabric along the pile side of the tension warp threads, the pile yarn consumption is minimal. Furthermore the positions of the tension warp yarns do not have to be altered in the course of the weaving. These can be kept between the two weft insertion paths. The tension warp weaving frame does not therefore have to be moved.